1. Field of the Invention
The present invention relates to method of producing electrolyzed water and apparatus for producing electrolyzed acidic water and electrolyzed alkaline water by electrolyzing water to be electrolyzed (which will be referred to as subject water hereinafter), and particularly to batch type electrolyzed water producing method and apparatus.
2. Description of the Related Art
In the electrolyzed water producing apparatus of this type, when subject water such as city water is supplied into an electrolytic cell, and DC current is supplied to between electrode plates, the electrolysis of the subject water is carried out in the electrolytic cell. Thus, cations such as calcium, sodium, magnesium and potassium ions contained (or intentionally added) in the city water are collected toward a cathode, i.e., into a cathode chamber. On the other hand, anions such as chlorine ion contained in the city water is collected toward an anode, i.e., into an anode chamber. During this time, because the anode and cathode chambers are partitioned by a membrane, only the electrolyzed acidic water is discharged through an outlet port provided in the anode chamber, and only the electrolyzed alkaline water is discharged through an outlet port provided in the cathode chamber.
The prior art electrolyzed water producing apparatus are classified into a continuous type one and a batch type one. The continuous type one is designed so that the subject water is electrolyzed while being continuously supplied to the electrolytic cell, and electrolyzed water is continuously supplied. On the other hand, batch type one is designed so that the subject water is temporarily accumulated in the electrolytic cell and then electrolyzed therein, and resulting electrolyzed water is supplied.
From the viewpoint that the electrolyzed water can be continuously supplied, the continuous type electrolyzed water producing apparatus is superior to the batch type one. However, if electrolyzed strongly acidic water or electrolyzed strongly alkaline water is intended to be continuously produced using the continuous type electrolyzed water producing apparatus, a large number of electrode plates are required from the relationship between the flow rate and the area of the electrode plate. This causes a disadvantage of an increased cost for the electrolyzed water producing apparatus.
In the continuous type electrolyzed water producing apparatus, the internal pressure in the electrolytic cell is increased. Therefore, in order to withstand such an internal pressure, the seal structure for the electrolytic cell is complicated, and/or the number of joint parts such as valves or the like is increased. Thereupon, an inexpensive batch type electrolyzed water producing apparatus is employed in many cases depending upon applications.
In the prior art batch type electrolyzed water producing apparatus, however, there is a problem that cations such as calcium and magnesium ions are deposited on the cathode plate upon electrolysis, and these deposits become scales to reduce the electrolyzing capability. For this reason, it is necessary to periodically replace the cathode plate by new one, and a user must always pay attention to take the frequency of replacement of the cathode plate. If the replacement is defaulted, electrolyzed water having a desired pH value is failed to be produced. Moreover, the proportion of cost occupied by the electrode plates in the electrolyzed water producing apparatus is extremely large, and handling of such expensive electrode plates as expendables has arrested the spread of the electrolyzed water producing apparatus.
The prior art batch type electrolyzed water producing apparatus is constructed to produce electrolyzed water having a desired pH value by controlling the electrolytic period of time. For example, a timer capable of adjusting the electrolytic period of time is mounted in the electrolyzed water producing apparatus, so that electrolyzed water having an intended pH value is produced by selecting an electrolytic period of time according to a user's preference.
However, the prior art batch type electrolyzed water producing apparatus is capable of re-electrolyzing the electrolyzed water resulting from the completion of the electrolysis and hence, in a few cases, the user performs the re-electrolysis of the electrolyzed water intentionally or by mistake. Therefore, it is difficult to correctly maintain and control the pH value of the electrolyzed water in the prior art batch type electrolyzed water producing apparatus.